Avocado Consumption, Abdominal Adiposity, and Oral Glucose Tolerance Among Persons with Overweight and Obesity

Abstract

Background Although intake of Hass avocado has been cross-sectionally linked to lower abdominal obesity, knowledge of the effects of avocado consumption on abdominal adiposity and glycemic outcomes remains limited. Objective The effects of avocado consumption on abdominal adiposity, insulin resistance, oral-glucose-tolerance test (OGTT), and estimated β-cell function were evaluated. Methods A total of 105 adults aged 25–45 y (61% female) with BMI ≥25 kg/m2 were randomly assigned to an intervention (N = 53) that received a daily meal with 1 fresh Hass avocado or a control (N = 52) that received an isocaloric meal with similar ingredients without avocado for 12 wk. DXA was used to assess the primary outcomes of abdominal adiposity [visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAAT), and the ratio of VAT to SAAT (VS Ratio)]. Fasted glucose and insulin were used to assess the primary outcomes of insulin resistance (HOMA-IR), and insulin sensitivity (Matsuda index) and β-cell function (Insulinogenic index) were estimated using an OGTT. Changes between groups were compared using an ANCOVA. Secondary analyses were conducted based on sex. Results The control group exhibited a greater reduction in SAAT [–54.5 ± 155.8 g (control) compared with 17.4 ± 155.1 g (treatment), P = 0.017] and increase in VS Ratio [0.007 ± 0.047 (control) compared with –0.011 ± 0.044 (treatment), P = 0.024]. Among females, the treatment group exhibited a greater reduction in VAT [1.6 ± 89.8 g (control) compared with –32.9 ± 81.6 g (treatment), P = 0.021] and VS Ratio [0.01 ± 0.05 (control) compared with –0.01 ± 0.03 (treatment), P = 0.001]. Among males, there was no significant difference between groups in changes in abdominal adiposity or glycemic outcomes. Conclusions Daily consumption of 1 fresh Hass avocado changed abdominal adiposity distribution among females but did not facilitate improvements in peripheral insulin sensitivity or β-cell function among adults with overweight and obesity. This study was registered at clinicaltrials.gov as NCT02740439.

A Comprehensive Review of Hass Avocado Clinical Trials, Observational Studies, and Biological Mechanisms

“…This study presents the first comprehensive review of Hass avocado clinical trials, observational studies, and biological mechanisms. We found that the Hass avocado has four major health benefits (Figure 17): (1) cardiovascular health [12][13][14][15][16][17][18][19][20][21][22]; (2), weight control [23][24][25][26][27][28][29][30]; (3) cognitive health [18,31,33]; and (4) colonic microbiota health [26,34]. We also found that four nutritional features were primarily responsible for all the major avocado health benefits: (1) high unsaturated to saturated fat ratio [7]; (2) viscous and prebiotic fiber [2,7]; (3) a relatively low energy density of 1.6 kcal/g [7]; and (4) high carotenoid bioavailability [35,36].…”

“…Four observational and five clinical studies evaluated the effects of Hass avocados on weight management or hunger and satiety [4,[23][24][25][26][27][28][29][30][31][32]. Current dietary guidelines recommend the consumption of an adequate intake of a variety of fresh fruits and vegetables to help maintain and achieve a healthy weight through reducing eating rate, lowering the total dietary energy density (ED), and increasing fiber intake by displacing other foods and snacks that are moderate to high in ED and low in fiber [1,31].…”

“…Two Hass avocado clinical trials support the daily intake of one daily avocado to help promote weight management when included in weight loss diets or in regular diets to lower visceral fat levels [26,27]. Three Hass avocado postprandial clinical trials showed that hunger was curbed, and meal satisfaction was increased over 3 to 6 h after the avocado was included at breakfast or lunch compared to the control meals [28][29][30].…”

“…A parallel RCT randomly assigned 105 adults (mean age 35 years, mean BMI 33) to an isocaloric daily meal with one Hass avocado or a control with similar foods without a Hass avocado for 12 weeks [27]. The consumption of a diet with a daily avocado altered abdominal fat distribution from baseline to 12 weeks in women but there were no improvements in body weight, insulin resistance (HOMA-IR), insulin sensitivity, or β-cell function in either men or women.…”

“…For weight control, avocados with an ED of 1.6 kcal/g (79% by weight of water and fiber) support better weight management and improve body composition [23][24][25][26][27][28][29][30][31][32]. Most fresh fruits have a high bulk volume and low energy density (ED), ranging from 0.3 to 1.6 kcal/g [2,[5][6][7].…”